/*-------------------------------------------------------------------------
 *
 * foreign.h
 *      support for foreign-data wrappers, servers and user mappings.
 *
 *
 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
 *
 * src/include/foreign/foreign.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef FOREIGN_H
#define FOREIGN_H

#include "nodes/parsenodes.h"


/* Helper for obtaining username for user mapping */
#define MappingUserName(userid) \
    (OidIsValid(userid) ? GetUserNameFromId(userid, false) : "public")


/*
 * Generic option types for validation.
 * NB! These are treated as flags, so use only powers of two here.
 */
typedef enum
{
    ServerOpt = 1,                /* options applicable to SERVER */
    UserMappingOpt = 2,            /* options for USER MAPPING */
    FdwOpt = 4                    /* options for FOREIGN DATA WRAPPER */
} GenericOptionFlags;

typedef struct ForeignDataWrapper
{
    Oid            fdwid;            /* FDW Oid */
    Oid            owner;            /* FDW owner user Oid */
    char       *fdwname;        /* Name of the FDW */
    Oid            fdwhandler;        /* Oid of handler function, or 0 */
    Oid            fdwvalidator;    /* Oid of validator function, or 0 */
    List       *options;        /* fdwoptions as DefElem list */
} ForeignDataWrapper;

typedef struct ForeignServer
{
    Oid            serverid;        /* server Oid */
    Oid            fdwid;            /* foreign-data wrapper */
    Oid            owner;            /* server owner user Oid */
    char       *servername;        /* name of the server */
    char       *servertype;        /* server type, optional */
    char       *serverversion;    /* server version, optional */
    List       *options;        /* srvoptions as DefElem list */
} ForeignServer;

typedef struct UserMapping
{
    Oid            umid;            /* Oid of user mapping */
    Oid            userid;            /* local user Oid */
    Oid            serverid;        /* server Oid */
    List       *options;        /* useoptions as DefElem list */
} UserMapping;

typedef struct ForeignTable
{
    Oid            relid;            /* relation Oid */
    Oid            serverid;        /* server Oid */
    List       *options;        /* ftoptions as DefElem list */
} ForeignTable;


extern ForeignServer *GetForeignServer(Oid serverid);
extern ForeignServer *GetForeignServerByName(const char *name, bool missing_ok);
extern UserMapping *GetUserMapping(Oid userid, Oid serverid);
extern ForeignDataWrapper *GetForeignDataWrapper(Oid fdwid);
extern ForeignDataWrapper *GetForeignDataWrapperByName(const char *name,
                            bool missing_ok);
extern ForeignTable *GetForeignTable(Oid relid);

extern List *GetForeignColumnOptions(Oid relid, AttrNumber attnum);

extern Oid    get_foreign_data_wrapper_oid(const char *fdwname, bool missing_ok);
extern Oid    get_foreign_server_oid(const char *servername, bool missing_ok);

#endif                            /* FOREIGN_H */
